Subject will be restored when possible |
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Gerard Trottet Submitted: 2007-12-27 20:24
Radio observations at 210 GHz taken by the BErnese Multibeam
RAdiometer for KOSMA (BEMRAK) are combined with hard X-ray and gamma-ray observations from the SONG instrument onboard CORONA-F and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to investigate high energy particle acceleration during the energetic solar flare of 2003 October 28. Two distinct components at submillimeter wavelengths are found. The first is a gradual, long-lasting (>30 min) component with large apparent source sizes (~60 arcsec).
Its spectrum below ~200 GHz is consistent with synchrotron
emission from flare-accelerated electrons producing
hard X-ray and gamma-ray bremsstrahlung assuming a magnetic field strength of
>200 G in the radio source and a confinement time of the radio-emitting
electrons in the source of less than 30 s. At even
higher frequencies, the spectrum deviates from synchrotron emission and
is increasing with frequency, as also seen in other large flares, but the
interpretation is unclear. The other component is impulsive and starts
simultaneously with high energy
(>200 MeV/nucleon) proton acceleration and the production of pions. The derived radio
source size is compact (<10 arcsec) and, within the uncertainties,
the emission is co-spatial with the location of precipitating
flare-accelerated >30 MeV protons as seen in Gamma-ray imaging
of the 2.2 MeV line emission.
The close correlation in time and space of radio emission with the
production of pions suggests that synchrotron emission of positrons
produced in charged-pion decay might be responsible for the observed
compact radio source. However, order-of-magnitude approximations rather
suggest that the derived numbers of positrons from
charged-pion decay are probably too small compared to
what is needed to produce the observed radio emission.
Synchrotron emission from energetic electrons therefore appears as the most
likely emission mechanism for the compact radio source seen in the
impulsive phase although it does not account for its close correlation, in time and space,
with pion production.
Authors: G. Trottet, S. Krucker, T. Luthi, A. Magun
Projects: CORONAS-F/SPIRIT,RHESSI,TRACE
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Publication Status: in press, ApJ
Last Modified: 2007-12-28 09:20
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Subject will be restored when possible |
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Gerard Trottet Submitted: 2007-12-27 20:22
Radio observations at 210 GHz taken by the BErnese Multibeam
RAdiometer for KOSMA (BEMRAK) are combined with hard X-ray and gamma-ray observations from the SONG instrument onboard CORONA-F and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to investigate high energy particle acceleration during the energetic solar flare of 2003 October 28. Two distinct components at submillimeter wavelengths are found. The first is a gradual, long-lasting (>30 min) component with large apparent source sizes (~60 arcsec).
Its spectrum below ~200 GHz is consistent with synchrotron
emission from flare-accelerated electrons producing
hard X-ray and gamma-ray bremsstrahlung assuming a magnetic field strength of
>200 G in the radio source and a confinement time of the radio-emitting
electrons in the source of less than 30 s. At even
higher frequencies, the spectrum deviates from synchrotron emission and
is increasing with frequency, as also seen in other large flares, but the
interpretation is unclear. The other component is impulsive and starts
simultaneously with high energy
(>200 MeV/nucleon) proton acceleration and the production of pions. The derived radio
source size is compact (<10 arcsec) and, within the uncertainties,
the emission is co-spatial with the location of precipitating
flare-accelerated >30 MeV protons as seen in Gamma-ray imaging
of the 2.2 MeV line emission.
The close correlation in time and space of radio emission with the
production of pions suggests that synchrotron emission of positrons
produced in charged-pion decay might be responsible for the observed
compact radio source. However, order-of-magnitude approximations rather
suggest that the derived numbers of positrons from
charged-pion decay are probably too small compared to
what is needed to produce the observed radio emission.
Synchrotron emission from energetic electrons therefore appears as the most
likely emission mechanism for the compact radio source seen in the
impulsive phase although it does not account for its close correlation, in time and space,
with pion production.
Authors: G. Trottet, S. Krucker, T. Luthi, A. Magun
Projects: CORONAS-F/SPIRIT,RHESSI,TRACE
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Publication Status: in press
Last Modified: 2007-12-27 20:22
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